Integrated heater for food packaging

ABSTRACT

The invention relates to a portable package and method for preparing a meal. A warm meal is prepared by taking dehydrated food within a package and combining it with non-boiling water. The mixture is then heated by an electrical, portable power source, such as a battery or vehicle power system. This allows a warm meal to be prepared almost anywhere, even without access to boiling water.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and incorporates by reference in itsentirety U.S. Provisional Application No. 60,696,521, filed Jul. 6,2005, titled “INTEGRATED HEATER FOR FOOD PACKAGING”.

TECHNICAL FIELD

The following relates to an apparatus and method for providing heatingwithin food packaging.

BACKGROUND

For many applications, quick-prepared food kits are necessary fornourishment when traditional cooking supplies are not accessible. Asexamples, military soldiers, astronauts, and recreational campers oftenmust rely upon food rations that will provide nourishing and fillingmeals without requiring a significant amount of time, effort, orsupplies to prepare for consumption. For some applications, the foodkits are known as “MREs”, or “meals ready to eat”.

One type of quick-prepared food kit consists of freeze-dried food withinsealed packaging. The freeze-dried food may include meat that alreadyhas been cooked before having been dehydrated for long-term storage andportability without refrigeration. To prepare the food, the consumeropens the package and pours approximately 1-2 cups of boiling waterinside. The food is hot once again in just a few minutes. The packagingcontains the food to enable the consumer to consume the meal directlyfrom the pouch. Typically, the serving size, calories, carbohydrates,sugars, and protein are pre-measured to ensure that a complete meal isincluded in the package.

While such food kits are portable and can be prepared very quickly witha minimum of tools and other supplies, it is still necessary to have asource of hot or boiling water to pour into the bag and re-hydrate thefood. For campers or hikers, the only source of hot water may be from acampfire. Military soldiers and astronauts may need to rely upon othersources for hot water, which may be inconvenient or rarely accessible.In some circumstances, this may significantly impact the usefulness ofthe product.

Since access to heated water is often limited, one known mechanism forheating MREs is to use a chemical heater pack to provide “self-heating.”Water is added to the packaging and the heater is placed next to thepackaging. The heater includes magnesium metal, which when mixed withwater, forms magnesium hydroxide, hydrogen, and heat. Typically, themeal is ready to be consumed within approximately 15 minutes.

SUMMARY BRIEF DESCRIPTION OF THE DRAWINGS

Additional embodiments will be more apparent upon consideration of thefollowing detailed description, taken in conjunction with theaccompanying drawings, in which like reference characters refer to likeparts throughout, and in which:

FIG. 1 is an illustration of packaging for a quick-prepared food kit;

FIG. 2 is a perspective view of packaging for a quick-prepared food kit;

FIG. 3 is an illustration of a heater integrated within packaging for aquick-prepared food kit in accordance with an embodiment of the presentinvention;

FIG. 4 is an illustration of electrode contacts and steam ventsintegrated within packaging for a quick-prepared food kit in accordancewith an embodiment of the present invention;

FIG. 5 is a schematic representation illustrating power source optionsand other circuitry for integrating a heater within packaging for aquick-prepared food kit in accordance with an embodiment of the presentinvention;

FIG. 6 is a chart providing power, current, and resistance requirementsfor a 250 ml quick-prepared food kit package, in accordance with anembodiment of the present invention;

FIG. 7 is a chart providing power, current, and resistance requirementsfor a 350 ml quick-prepared food kit package, in accordance with anembodiment of the present invention;

FIG. 8 is a chart providing heater calculations for a 12 V DC powersupply; and

FIG. 9 is a chart providing heater calculations for a 28 V DC powersupply.

DETAILED DESCRIPTION

The following discloses a heater assembly is integrated within packagingof a quick-prepared food kit. Preferably, the heating assembly uses oneor more flexible, semiconductive, electrically resistive heatingelements powered by a source of electrical power. This embodiment'sheater assembly withstands the stresses that can break and disconnect anelectrical wire-based heater and efficiently provides quick heatingcapability with reduced power requirements. The integrated heater isdesigned to be disposable once the meal within the packaging isconsumed.

FIGS. 1 and 2 illustrate exemplary quick-prepared food kits, or “MREs”that may be adapted to incorporate the integrated heating system inaccordance with the present invention. The packaging consists of aflexible foil 20 that is designed to keep the food sealed from externalelements. The packaging is lightweight, easily portable, compressible,and durable to impact. The exterior laminate(s) may use common materialssuch as nylon, polyethylene, polypropylene, polyester, or metal film,along with printed layers for branding and instructions. In someembodiments, to unseal the packaging, a tear portion 10 is included toenable consumers to easily tear open the packet without requiring anytools.

FIG. 3 illustrates an integrated heating system that may be used inaccordance with an embodiment of the present invention. Although theoutside packaging 34 appears as a standard, quick-prepared food kit, theinterior of the packaging 32 includes a semiconductive heating element30, preferably in a serpentine configuration. The inner laminate withinthe packaging may be made of any of nylon, polyethylene, polypropylene,polyester, metal film, or other common materials in the packagingindustry.

The heating element is flexible to bend along with the packaging 34.Metallic contacts 33 a and 33 b connect to a power source to provide anelectrical circuit to turn on the heater and start warming the packageonce water is added. In some embodiments, water is already added suchthat all that is needed is heating provided by the heating assembly.

The resistive heating element may include, for example, but is notlimited to a graphite or carbon foil, or it may be a felt or fabricencased within the packaging. The heating element is designed for theintended power source, such as a 12 V DC automobile or a 28 V DCmilitary system.

In one example, the metallic contacts 33 a and 33 b can be connected toa military vehicle, using on-board power device clamps. As anotherexample, the contacts can be connected to a vehicle power adapter, suchas through a cigarette lighter. As further examples, the contacts alsomay be connected to a rechargeable power device or to vehicle batteryterminals.

FIG. 4 illustrates an optional protective label cover for the exteriorof the packaging, in accordance with a further exemplary embodiment ofthe invention. Flexible packaging 40 includes a protective label cover43, which peels back to expose a terminal 42 and a micro-perforatedsteam vent 44. This protects the vent and terminal during transport andstorage while enabling easy access during heating. When the protectivelabel is fully removed from the packaging 45, both terminals 46 and 47are exposed, along with the vent 48. The micro perforations in the ventallow steam to vent but impede liquid water from exiting, for properheating in some circumstances.

FIG. 5 illustrates a schematic with several possible power sources andother circuitry that may be associated with the heating system.Particularly, the heater 50 can connect through contacts 51 a and 51 bto a car adaptor 52 a, vehicle battery terminals 52 b, an in-vehicleconnection 52 c, a rechargeable device 52 d, or other power sources. Thespacing of the contacts 51 b and 51 a can be determined to easilyconnect the packaging to battery terminals having the same geometry. A12 V DC power source is acceptable, although 28 V DC is preferred tominimize heating time. The heater element geometry varies according tothe voltage and power requirements, as will be described further below.

As also shown in FIG. 5, the packaging may also optionally include anover-current fuse 54 to prevent damage to the input power source.

Significantly, as an optional embodiment, the heating element canadditionally include a thermal fuse 53 designed to create an opencircuit when the food and water have received a determined amount ofheat energy. This is useful to prevent overcooking or undercooking. Athermal fuse indicator, such as an LED, can be included to inform theconsumer that the meal in the food kit has been prepared appropriately.

FIG. 6 is a chart providing power, current and resistance requirementsfor a 250 ml quick-prepared food kit package, in accordance with anembodiment of the present invention. As can be seen, assuming a packagethat can contain 250 ml of water, with an initial temperature of 20° C.and a desired final temperature of 95° C., charts are provided thatindicate the power, current, and resistance for given times and time,current, and resistance for given power to temperature. Similarly, FIG.7 is a chart providing power, current, and resistance and time, current,and resistance for an integrated heater used in a 350 ml package. Thepackage can be made in other sizes as well. Various pre-proportionedquantities of food can be packaged with instructions for the appropriateamount of water to add.

FIG. 8 is a chart providing heater calculations for a 12 V DC powersupply. Particularly, for a 12 V supply, as power is varied, thecurrent, resistance, and length to width ratio is provided. As thelength is varied, the width and area are provided as well.

Lastly, FIG. 9 is a chart providing heater calculations for a 28 V DCpower. Similar to FIG. 8, as power is varied, the current, resistance,and length to width ratio is provided. As the length is varied, thewidth and area are provided as well.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thespirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. A portable food packaging assembly comprising: a handheld bag forenclosing a food product; a heater element in direct contact with thebag; and first and second electrical terminals in electrical contactwith the heater element, wherein when power is supplied to the terminalsthe heater element generates heat to warm food within the bag.
 2. Thefood packaging assembly of claim 1, further comprising a tear strip sealportion for opening the assembly to consume the food product.
 3. Thefood packaging assembly of claim 1, wherein the heater element issemiconductive foil.
 4. The food packaging assembly of claim 1, whereinthe heater element is graphite foil.
 5. The food packaging assembly ofclaim 1, wherein the heater element is semiconductive felt orsemiconductive fabric.
 6. The food packaging assembly of claim 1,wherein the bag is made from material selected from the group consistingof nylon, polyethylene, polypropylene, polyester, and metal film.
 7. Thefood packaging assembly of claim 1, wherein the bag further comprises amicro-perforated vent.
 8. The food packaging assembly of claim 1 furthercomprising a fuse.
 9. The food packaging assembly of claim 8, whereinthe fuse further comprises an indicator for indicating when food isappropriately prepared.
 10. The food packaging assembly of claim 1,wherein said power is supplied from a source selected from the groupconsisting of 12 V DC, 28 V DC, one or more batteries, one or more fuelcells, and one or more rechargeable batteries.
 11. The food packagingassembly of claim 1, wherein said power is selected from the groupconsisting of a vehicle accessory jack, an in vehicle connection, directbattery contacts, and a rechargeable device.
 12. The food packagingassembly of claim 1, wherein the micro-perforated vent has openingssized such that steam may exit said self-contained food preparationapparatus and said openings sized such that liquid water may not exitsaid self-contained food preparation apparatus.
 13. A portable foodpreparation apparatus comprising: a flexible container comprising aninterior area and a food holding area; a flexible heating elementpositioned within the interior area; a first electrical contact; and asecond electrical contact, wherein the flexible heating element iselectrically in series with said first electrical contact and saidsecond electrical contact.
 14. The portable food preparation apparatusof claim 13, wherein the flexible container includes a seal that can beopened by hand.
 15. The portable food preparation apparatus of claim 13,wherein the flexible heating element is a semiconductor.
 16. Theportable food preparation apparatus of claim 13, wherein the flexiblecontainer further comprises a vent having a plurality of openings sizedsuch that steam may pass through the openings but liquid water isimpeded from passing therethrough.
 17. A food packaging apparatuscomprising a food holding area; a heater element; a micro-perforatedvent; and first and second electrical terminals, wherein the first andsecond electrical terminals are electrically connected to the heaterelement, and wherein when power is supplied to the first and secondelectrical terminals the heater element generates heat.
 18. The foodpackaging apparatus of claim 17, wherein the micro-perforated vent has aplurality of openings sized such that steam may pass through the openingbut liquid water is impeded from passing therethrough.
 19. The foodpackaging apparatus of claim 17, wherein the heater element is asemiconductor.
 20. The food packaging apparatus of claim 17, wherein theheater element is graphite foil.
 21. The food packaging apparatus ofclaim 17 further comprising a removable protective cover that covers themicro-perforated vent and the first and second electrical terminals.